Sum of Diagonal elements

CODE:

import java.util.*;

class Diagonal

{

     public static void main(String args[])

     {

           int m,n,i,j,sum=0;

           Scanner sc = new Scanner(System.in);

           System.out.print("Enter no of rows & columns :");

           m=sc.nextInt();

           n=m

           int a[][]=new int[m][n];

           for(i=0;i<=m-1;i++)

           {

                for(j=0;j<=n-1;j++)

                {

                     System.out.print("enter a no:");

                     a[i][j]=sc.nextInt();

                }

           }

           for(i=0;i<=m-1;i++)

           {

                for(j=0;j<=n-1;j++)

                {

                     if(i==j)

                     sum=sum+a[i][j];

                }

                System.out.println("Sum="+sum);

           }

     }

} 

OUTPUT: